Alright.... I don't want to have anyone think poorly of me for saying this but once upon a time I was an OSI agent for the Air Force. I can tell you just about anything you want to know about what they do and do not do. Bottom line is this:
1. They only test for rec drugs as stated before. In order to test you for anything else you must be suspected and you have to be requested by your commander. It costs uncle sugar a lot of money to test you and it is rare.
2. Most of the time "the bad man" is not going to try to set you up to buy something like gear. I worked specifically with drugs for four years as an agent and I NEVER nor did I EVER see an agent try to bag someone for gear. I have seen individuals get busted because they got huge too fast. If you use common sense and you don't bulk up too fast you will be fine.
3. If someone supects you and tells anyone up in your chain of command and it makes it to the commander you are fucked plain and simple. You will get a dishonorable and you will probably do some time with Bubba, Tiny, and Snowflake. If you are lucky you will just get the dishonorable but that is as good as it could get.
I wanted to reiterate that I am not doing that job anymore, I'm no longer in the military, and I'm just giving you my 2 cents to help you out. If you have any more questions send me a message. If I don't know, I can point you in the right direction.
Don't forget, if you live on base or work on base you can be searched at any time (because you are on their property). They are not civilian police and they do not have to follow the same rules concerning resonable doubt (to a degree). However, if they want to search your car tell them NO (even though the sign on the gate says they can at any time, that's not 100% accurate and resonable doubt applies). Most likely you will just get escorted off base. I could go into this more but it would take more time than it is worth.